Elderly people living alone or in assisted living facilities are susceptible to medical emergencies in which they are alive but unconscious. In such a case, they often require medical assistance within a short time after falling unconscious. For example, an elderly person can have an immobilizing stroke, heart attack or go into diabetic shock or coma. In such a case they are not able to move in order to call for assistance. In many cases if help is received quickly, the immobilized person has an improved prognosis and increased rate of recovery from the immobilizing ailment. In some cases, delay of many hours is fatal to the person.
It is desirable to have a compact, lightweight low cost, accurate sensor system to provide data that is used to summon assistance in the event of an immobilizing medical problem. It is desirable for the sensor to be small and lightweight so it is comfortable for the monitored person to wear. Otherwise the monitored person is likely to take it off.